This invention relates to arrangements for storing and supplying unit quantities of hot melt ink for use in hot melt ink printing systems and, more particularly, to a new and improved hot melt ink supply unit which effectively protects the hot melt ink during storage and transit and permits delivery of the ink in a simple and convenient manner to a molten ink reservoir without contamination.
In printing systems which use inks that are solid at room temperature and melted by heating for application to an ink-receiving substrate, such as certain ink jet printing systems, the solid ink must be delivered to a molten ink reservoir associated with the printing system in such a way that contamination of the ink is avoided. In addition, where different colored inks are contained in different reservoirs in the printing system, care must be taken to assure that ink of the proper color is delivered to the corresponding reservoir. Furthermore, exposure of the operator to molten ink splashed from the reservoir when solid ink is delivered must be avoided.
Heretofore, hot melt ink has been supplied to reservoirs in ink jet systems by selective heating of ink in a replaceable cartridge as described, for example, in U.S. Pat. No. 4,631,557, by selective heating of an ink block as described in U.S. Pat. No. 4,593,292, or by advancing ink pellets or granules toward the reservoir by a complex pellet drive or granule conveyer system as described in U.S. Pat. Nos. 4,636,803 and 4,667,206. Those arrangements, however, require either melting of the ink in a cartridge or block outside the reservoir to transfer ink into the reservoir or necessitate complicated mechanical advancing and delivery systems to move pellets or granules from a supply into a reservoir. Thus, the prior art does not permit simple and convenient manual loading of individual solid hot melt ink supply units without exposing the solid ink to potential contamination and the operator to possible injury from splashing of molten ink in the reservoir.